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Günther Ohloff
Günther Ohloff (21 July 1924 in Gvardeysk, Tapiau near Königsberg – 9 November 2005 in Bernex, Switzerland, Bernex near Geneva) was a prominent Germans, German fragrance chemist. Life Ohloff was raised in East Prussia. When World War II erupted, he served in the German military, serving on the Eastern Front. He was severely wounded during the Battle of Stalingrad. After the war he studied Pharmacy at the University of Königsberg and University of Erlangen-Nuremberg, Erlangen, as well as Chemistry at the Dresden University of Technology, Technische Hochschule Dresden. He received a PhD in 1951, based on his work on the condensation of terpenes with formaldehyde (Prins reaction) unter the direction of Heinrich Wienhaus.Ferdinand Näf, Wilhelm Pickenhagen: ''Günther Ohloff (1924–2005)'', ''Nachrichten aus der Chemie'' ''54'' (2006), 335 Career Ohloff began his career in 1951 with in Miltitz near Leipzig, at that time the most renowned flavor and fragrance company. In 1953 h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gvardeysk
Gvardeysk ( rus, Гварде́йск, p=ɡvɐrˈdʲejsk, a=RU-Gvardejsk.ogg), known prior to 1946 by its German name ( lt, Tepliava; pl, Tapiawa/Tapiewo), is a town and the administrative center of Gvardeysky District in Kaliningrad Oblast, Russia, located on the right bank of the Pregolya River east of Kaliningrad. Population figures: It is located within the historic region of Sambia. History Peter of Dusburg wrote of a settlement known as Tapiow, first documented in 1254, and the neighboring fort ''Surgurbi'' built by 1265.Oesterley, p. 676 The Old Prussian names were derived from the words ''tape'', ''teplu'', ''toplu'', ''tapi'', meaning "warm", and ''sur garbis'', meaning "around the mountain". During the 13th century Prussian Crusade, the area was conquered by the Teutonic Knights. To protect Samland from the Nadruvians and Scalvians, the crusaders built a wooden fort between the Deime and Pregel Rivers in 1283–1290. This was replaced by Tapiau Castle, a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formaldehyde
Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section Forms below), hence it is stored as an aqueous solution (formalin), which is also used to store animal specimens. It is the simplest of the aldehydes (). The common name of this substance comes from its similarity and relation to formic acid. Formaldehyde is an important precursor to many other materials and chemical compounds. In 1996, the installed capacity for the production of formaldehyde was estimated at 8.7 million tons per year. It is mainly used in the production of industrial resins, e.g., for particle board and coatings. Forms Formaldehyde is more complicated than many simple carbon compounds in that it adopts several diverse forms. These compounds can often be used interchangeably and can be interconverted. *Molecular formald ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eschenmoser Fragmentation
The Eschenmoser fragmentation, first published in 1967, is the chemical reaction of α,β-epoxyketones (1) with aryl sulfonylhydrazines (2) to give alkynes (3) and carbonyl compounds (4). The reaction is named after the Swiss chemist Albert Eschenmoser, who devised it in collaboration with an industrial research group of Günther Ohloff, and applied it to the production of muscone and related macrocyclic musks. The reaction is also sometimes known as the Eschenmoser–Ohloff fragmentation or the Eschenmoser–Tanabe fragmentation as Masato Tanabe independently published an article on the reaction the same year. The general formula of the fragmentation using ''p''-toluenesulfonylhydrazide is: :: Several examples exist in the literature, and the reaction is also carried out on industrial scale. Reaction mechanism The mechanism of the Eschenmoser fragmentation begins with the condensation of an α,β-epoxyketone (1) with an aryl sulfonylhydrazine (2) to afford the intermediate hydra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambergris
Ambergris ( or , la, ambra grisea, fro, ambre gris), ''ambergrease'', or grey amber is a solid, waxy, flammable substance of a dull grey or blackish colour produced in the digestive system of sperm whales. Freshly produced ambergris has a marine, fecal odor. It acquires a sweet, earthy scent as it ages, commonly likened to the fragrance of Isopropyl alcohol without the vaporous chemical astringency. Ambergris has been highly valued by perfume makers as a fixative that allows the scent to endure much longer, although it has been mostly replaced by synthetic ambroxide. Dogs are attracted to the smell of ambergris and are sometimes used by ambergris searchers. Etymology The word ''ambergris'' comes from the Old French "''ambre gris''" or "grey amber". The word "amber" comes from the same source, but it has been applied almost exclusively to fossilized tree resins from the Baltic region since the late 13th century in Europe. Furthermore, the word "amber" is derived from the Mid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firmenich
Firmenich SA is a private Swiss company in the fragrance and flavor business. It is the largest privately owned company in the field and ranks number two worldwide. Firmenich has created perfumes for over 125 years and produced a number of well-known flavors. Firmenich employs 10,000 people across 46 manufacturing plants and six research and development centers. Major competitors include Givaudan, International Flavors and Fragrances and Symrise. In 2021, Firmenich was ranked second on FoodTalks' Global Top 50 Food Flavours and Fragrances Companies list, below Givaudan and above International Flavors and Fragrances. History The company was founded as Chuit & Naef in 1895 in Geneva by chemist Philippe Chuit and businessman Martin Naef. Fred Firmenich joined in 1900 and later became the majority partner. The company was renamed Firmenich SA. Originally a fragrance company, Firmenich branched into the flavor business by creating a raspberry substitute in 1938, followed by creati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmatropic Reaction
A sigmatropic reaction in organic chemistry is a pericyclic reaction wherein the net result is one sigma bond, σ-bond is changed to another σ-bond in an uncatalyzed intramolecular reaction. The name ''sigmatropic'' is the result of a compound word, compounding of the long-established sigma designation from single carbon–carbon bonds and the Greek word ''tropos'', meaning turn. In this type of rearrangement reaction, a substituent moves from one part of a pi-bond, π-bonded system to another part in an intramolecular reaction with simultaneous rearrangement of the π system. True sigmatropic reactions are usually uncatalyzed, although Lewis acid catalysis is possible. Sigmatropic reactions often have transition-metal catalysts that form intermediates in analogous reactions. The most well-known of the sigmatropic rearrangements are the [3,3] Cope rearrangement, Claisen rearrangement, Carroll rearrangement, and the Fischer indole synthesis. Overview of sigmatropic shifts Woodward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ene Reaction
In organic chemistry, the ene reaction (also known as the Alder-ene reaction by its discoverer Kurt Alder in 1943) is a chemical reaction between an alkene with an allylic hydrogen (the ene) and a compound containing a multiple bond (the enophile), in order to form a new σ-bond with migration of the ene double bond and 1,5 hydrogen shift. The product is a substituted alkene with the double bond shifted to the allylic position. This transformation is a group transfer pericyclic reaction, and therefore, usually requires highly activated substrates and/or high temperatures. Nonetheless, the reaction is compatible with a wide variety of functional groups that can be appended to the ene and enophile moieties. Many useful Lewis acid-catalyzed ene reactions have been also developed, which can afford high yields and selectivities at significantly lower temperatures, making the ene reaction a useful C–C forming tool for the synthesis of complex molecules and natural products. Ene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Singlet Oxygen
Singlet oxygen, systematically named dioxygen(singlet) and dioxidene, is a gaseous inorganic chemical with the formula O=O (also written as or ), which is in a quantum state where all electrons are spin paired. It is kinetically unstable at ambient temperature, but the rate of decay is slow. The lowest excited state of the diatomic oxygen molecule is a singlet state. It is a gas with physical properties differing only subtly from those of the more prevalent triplet ground state of O2. In terms of its chemical reactivity, however, singlet oxygen is far more reactive toward organic compounds. It is responsible for the photodegradation of many materials but can be put to constructive use in preparative organic chemistry and photodynamic therapy. Trace amounts of singlet oxygen are found in the upper atmosphere and also in polluted urban atmospheres where it contributes to the formation of lung-damaging nitrogen dioxide. It often appears and coexists confounded in environments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mülheim
Mülheim, officially Mülheim an der Ruhr () and also described as ''"City on the River"'', is a city in North Rhine-Westphalia in Germany. It is located in the Ruhr Area between Duisburg, Essen, Oberhausen and Ratingen. It is home to many companies, especially in the food industry, such as the Aldi Süd Company, the Harke Group and the Tengelmann Group. Mülheim received its town charter in 1808, and 100 years later the population exceeded 100,000, making Mülheim officially a city. At the time of the city's 200th anniversary with approximately 170,000 residents, it was counted among the smaller cities of Germany. Geography Geographical location Mülheim an der Ruhr is located to the southwest of Essen in the Ruhr valley. Geology The northern foothills of the Rhenish Massif are characterised by the distinctive rock formation of the bare mountain slopes through which run coal-bearing layers which formed during the carboniferous period. Here the Ruhr cuts more than 50 meter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Max Planck Institute For Bioinorganic Chemistry
The Max Planck Institute for Chemical Energy Conversion (MPI CEC) is a research institute of the Max Planck Society. It is located in the German town of Mülheim. Research The MPI CEC investigates fundamental chemical processes in energy transformation and contributes to the development of new and efficient catalysts. Its approach to this problem is based on a profound understanding of the underlying chemical reactions and multidisciplinary. Departments Inorganic Spectroscopy Director: Serena DeBeer The department of Inorganic Spectroscopy focuses on the development and application of advanced X-ray spectroscopic tools for understanding processes in biological and chemical catalysis. Research groups * Energy Converting Enzymes (James Birrell) *Computational Chemistry (Ragnar Björnsson) *Biochemistry of Metalloproteins (Laure Decamps) *X-ray Spectroscopy Instrumentation (Sergey Peredkov) *Chemical Synthesis (Christina Römelt) *Proteins on electrodes (Olaf Rüdiger) *Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holzminden
Holzminden (; nds, Holtsminne) is a town in southern Lower Saxony, Germany. It is the capital of the district of Holzminden. It is located on the river Weser, which at this point forms the border with the state of North Rhine-Westphalia. History Holzminden is first mentioned in the 9th century as ''Holtesmeni''. However, the name did not at this time refer to the present city, but to the village of Altendorf, the "old village", which was incorporated into the city in 1922. During the reign of Louis the Pious (814–840), monks from the Abbey of Corbie in France came to this part of Germany and founded a daughter house at Hethis in the Solling. As it became clear that this site was unviable (owing to lack of access to water) it was abandoned, and a new monastery, ''Corbeia nova'' (Corvey Abbey), opened close to the river. Old documents show that many pious donations were given to the ''Holtesmeni'' (monastery). The settlement is believed to have come into being, along with oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symrise
Symrise AG is a major producer of flavours and fragrances with sales of €3.154 billion in 2018. Major competitors include Döhler, Firmenich, Givaudan, International Flavors and Fragrances, and Takasago International. Symrise is a member of the European Flavour Association. In 2021, Symrise was ranked 4th by FoodTalks' Global Top 50 Food Flavours and Fragrances Companies list. History Symrise was founded in 2003 by the merger of Bayer subsidiary Haarmann & Reimer (H&R) and Dragoco, both based in Holzminden, Germany. Haarman & Reimer Haarman & Reimer (H&R) was founded in 1874 by chemists Ferdinand Tiemann and Wilhelm Haarmann after they succeeded in first synthesizing vanillin from coniferin. Holzminden was the site where vanillin was first produced industrially. In 1917, H&R supported Leopold Ružička's unsuccessful three-year project to synthesize irone, a fragrance of violets. In 1953, H&R was acquired by Bayer. Dragoco Dragoco was founded in 1919 by Carl-Wilhelm Gerbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
